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| United States Patent |
5,622,236
|
|
Azumi
, et al.
|
April 22, 1997
|
Guidance system for self-advancing vehicle
Abstract
A guidance system for a self-advancing vehicle such as a floor washing
machine is provided in an arrangement which does not spoil the beauty of,
for example, a floor surface, which can be reused multiple times, which is
low in cost and which more reliably follows a guidance line. A guidance
line is drawn with a luminous material or with a coating material mainly
consisting thereof along a predetermined traveling path on a floor
surface. The guidance line is drawn on the floor surface with a mixture in
which the luminous material is dissolved or dispersed in a solvent.
Alternatively, a mixture in which the luminous material is mixed with a
coating agent such as floor polish or wax is applied to the floor surface
to draw the guidance line. The luminous material is, for example, an
ultraviolet-absorbing material, an infrared-absorbing material or a
visible light-absorbing material. A self-advancing floor washing machine
using the present invention comprises a traveling device with two casters
and two independent drive wheels, the latter of which are guided by a
combination of one or more photosensors which track the guidance line and
send a signal to a control unit that controls the drive wheels. Based on
the signals from the photosensors, the machine is guided along the
guidance line.
| Inventors:
|
Azumi; Yasuhiro (Kanagawa, JP);
Sado; Mitsuo (Kanagawa, JP)
|
| Assignee:
|
S. C. Johnson & Son, Inc. (Racine, WI)
|
| Appl. No.:
|
447323 |
| Filed:
|
May 22, 1995 |
Foreign Application Priority Data
| Current U.S. Class: |
180/168; 180/169; 318/587 |
| Intern'l Class: |
B62D 001/02 |
| Field of Search: |
180/167,168,169
364/424.02,424.01
318/587,580
|
References Cited
| Foreign Patent Documents |
| 57-128119 | Aug., 1982 | JP.
| |
| 2-56610 | Feb., 1990 | JP.
| |
| 3-237958 | Oct., 1991 | JP.
| |
Other References
Abstract of Japanese Published patent application No. 06-149350 from JAPIO
Japanese Patent Computer Database (one page).
|
Primary Examiner: Camby; Richard M.
Attorney, Agent or Firm: Rakoczy; R. E., Frank; J. W.
Claims
What is claimed is:
1. A guidance system for a self-advancing vehicle comprising
A. a guidance line on a surface over which the vehicle is to pass wherein
the guidance line comprises a luminous material that emits light of a
first wavelength when excited by light of a second wavelength from a light
emitter means wherein the guidance line is drawn onto the surface using a
composition selected from the group consisting of the luminous material
dissolved or dispersed in a solvent and the luminous material dissolved or
dispersed in a coating composition; and
B. at least one photosensor that is oriented to pass over the guidance
line, the photosensor comprising the combination of
(1) the light emitter oriented to beam the light of the second wavelength
onto the guidance line and working in cooperation with
(2) a light receiver oriented to detect the light of the first wavelength
emitted from the guidance line when the light of the second wavelength is
beamed onto the guidance line wherein the light receiver generates a first
signal proportional to the amount of first wavelength light being
received;
C. a control unit means for receiving the signal from the light receiver
and, in response to the first signal, sending a second signal to
D. a steering means on the vehicle such that the second signal causes the
steering means to orient the vehicle in such a mariner as to maintain the
photosensor over the guidance line and thereby cause the vehicle to follow
the guidance line as it advances.
2. The system as claimed in claim 1 wherein there are two photosensors,
each of which provides a signal to the steering means to cause the vehicle
to follow the guidance line as it advances.
3. The system as claimed in claim 1 wherein the luminous material is
selected from the group consisting of an ultraviolet-absorbing material,
an infrared-absorbing material, and a visible light-absorbing material.
4. The system as claimed in claim 3 wherein the luminous material is not
normally visible to the eye.
5. The system as claimed in claim 1 wherein the luminous material is
dissolved in a floor polish.
6. The system as claimed in claim 1 wherein a protective coating agent is
applied over the guidance line.
7. The system as claimed in claim 1 wherein there is only one photosensor
present and the guidance means is set to generally turn the vehicle to one
side away from the guidance line and the signal sent from the photosensor
causes the guidance means to turn the vehicle in towards the opposite side
and thereby cause the vehicle to follow the guidance line as it advances.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a guidance system for a self-advancing
vehicle such as a floor washing machine, which is arranged to control the
traveling direction of the self-advancing vehicle along a guidance line
drawn along a predetermined traveling path on a floor surface.
2. Related Background Art
Self-advancing vehicles that perform various operations without an operator
while automatically traveling on a floor surface, for example such as
automatic floor washers, vacuum cleaners, or carrying vehicles, are known.
One such conventional guidance system for automatically controlling the
traveling direction is described in Japanese Published Patent Application
No. 57-128119 to Isamu. It teaches a system for guiding the self-advancing
vehicle used a photosensor attached to the self-advancing vehicle that
detected reflected light from a reflective tape which was previously
adhered onto the floor surface along an intended traveling path.
The above guidance system with reflective tape, however, had such problems
that the reflective tape was conspicuous and spoiled the beauty.
Particularly in the case of floor washers, a rotary brush could abrade or
peel off the reflective tape. That required frequent tape exchange, and
thus created problems for wide areas.
There was another conventional system described in Japanese Published
Patent Application No. 3-237958 to Hidetaka et. al. in which a laser
source was set on the ceiling to emit a laser beam toward the floor
surface. The traveling direction was controlled by detecting the laser
beam using a photosensor mounted on the self-advancing vehicle.
This laser beam guidance system, however, had problems in that costs for
apparatus and installation were high and that it could become disabled
when the laser beam was interrupted by an obstacle or the like.
Japanese Published Patent Application No. Hei 2[1990]-56610 to Toshihiro et
al. teaches an optical guidance system for moving vehicles. A guide path
is coated with a strip of transparent paint that selectively absorbs or
reflects light outside of the visible range. A series of three sensors
detects light absorbed or reflected from the paint to keep the moving
vehicle following the paint line. The center sensor detects the paint
strip. The other two sensors monitor the unpainted floor and detect when
the vehicle is moving off the paint strip. They steer the vehicle back to
following the paint strip. One problem with this system is that dirt on
the floor makes it harder for the sensors to keep the vehicle following
the paint strip because the dirt makes the paint strip harder to
distinguish from the floor next to the strip.
SUMMARY OF THE INVENTION
The present invention has been accomplished to solve the above problems
with conventional systems. An object of the invention is to provide a
guidance system for a self-advancing vehicle which does not spoil the
beauty of the floor surface, which can be reused multiple times, and which
is low in cost.
A guidance system for self-advancing vehicle according to the present
invention is characterized in that a guidance line is drawn with a
luminous material or a coating material mainly consisting thereof along a
predetermined traveling path on the floor surface. The traveling direction
of the self-advancing vehicle is controlled by detecting light emitted
from the luminous matter by mean of a photosensor provided on a
self-advancing vehicle. The luminous material is dissolved or dispersed in
a solvent, or is mixed with a coating agent such as floor polish, and the
mixture is applied onto the floor surface to draw a guidance line. The
luminous coloring material may be an ultraviolet-absorbing material, an
infrared-absorbing material, or a visible-light-absorbing material. A
protective coating agent such as floor polish is applied onto the guidance
line thus drawn to protect it from abrasion.
Effects of the guidance system according to the present invention are as
follows.
(1) Since the guidance line is drawn with the luminous matter, specifically
the ultraviolet-absorbing material or the infrared-absorbing material,
etc., which is rarely observed by the eye or is inconspicuous, the beauty
of the floor surface is not spoiled.
(2) Since the coating agent such as floor polish is applied over the
luminous material deposited on the floor surface, the luminous material
can be reused multiple times for as long as the coating agent such as
floor polish remains.
(3) Since no extra construction is needed for buildings or the like, this
system can be provided at low cost.
(4) Since in the preferred embodiment, the photosensor directly tracks the
luminous material in the guidance line only, dirt covering the guidance
line is less likely to cause the self-advancing vehicle to deviate from
the guidance line.
Further objects and effects of the invention will be apparent from the
description of the preferred embodiments as illustrated in the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a side view of a floor washing machine, and FIG. 1B is a plan
view thereof along A--A line of FIG. 1A;
FIG. 2 is an explanatory drawing to illustrate a method for correcting the
traveling direction using a guidance system according to the present
invention; and
FIG. 3 is a drawing to show another method for correcting the traveling
direction using another guidance system according to the present invention
.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiments of the present invention will be described with reference
to the accompanying drawings. In FIGS. 1A and 1B, reference numeral 1
designates a guidance line, which was drawn with a luminous material or a
coating material mainly consisting thereof along a predetermined traveling
path on a floor surface 2. A self-advancing floor washing machine V is
guided to travel along guidance line 1.
The guidance line 1 is drawn on the floor surface 2 by applying a mixture
in which the luminous material is dissolved or dispersed in a solvent, to
the floor surface 2. Alternatively, a mixture in which the luminous
material is mixed in a coating agent such as floor polish may be applied
to the floor surface 2 to form the guidance line 1. This guidance line 1,
that is, the luminous material thus drawn, is normally coated with about
three layers of a protective coating agent such as floor polish, but the
invention is by no means limited to this.
The luminous material may be selected for example from
ultraviolet-absorbing materials, infrared-absorbing materials, and
visible-light absorbing materials. The ultraviolet-absorbing materials are
materials having such characteristics (luminescence) that they are excited
with absorption of light in the ultraviolet region and then emit
wavelength-converted light in the visible region when returning from an
unstable excited state to a stable ground state. Similarly, the
infrared-absorbing materials are materials absorbing light in the infrared
wavelength region to emit visible rays, and the visible-light-absorbing
matters are materials absorbing light in a certain visible wavelength
region to emit light in another region different in wavelength therefrom.
Particularly preferable from the viewpoint of retaining the floor beauty
are materials of a type which are colorless and not normally visible to
the eye and which do not spoil a color tone of the floor surface.
The floor washing machine V is a traveling device consisting of two drive
wheels 3, 3' set left and right in the rear part of the machine and two
casters 4 set left and right in the front part, etc., a guidance device
consisting of two photosensors 5, 5' and a controlling unit 6, and a
washing device consisting of a rotary brush 7, a detergent tank 8, a dirty
water tank 9, and a squeegee 10.
The left drive wheel 3' and right drive wheel 3 are driven to rotate
independently of each other by respective drive motors 11, 11' for
exclusive use by each wheel. Accordingly, by driving motor 11 to rotate
only the right drive wheel 3, the floor washing machine V can turn about
the left drive wheel 3'. Conversely, by driving motor 11' to rotate only
the left drive wheel 3', the machine can make a right turn. Further, the
machine can advance drawing a curve of a desired size to the right or to
the left by rotating speeds of the left drive wheel 3' and right drive
wheel 3 at different speeds from each other. Moreover, by reversing the
drive wheels 3, 3', the floor washing machine V can recede (or move
backward). In addition, the machine can make a quick turn by rotating the
left drive wheel 3' and right drive wheel 3 in mutually opposite rotation
directions. While a two-drive wheeled vehicle is shown, it is understood
that other drive means such a treads, tracks or other propulsion means can
be used equally well.
Each photosensor 5, 5' is mainly composed of a light-emitting device such
as a light-emitting diode and a light-receiving device such as a photo
transistor. The light-emitting device emits light of a predetermined
wavelength (ultraviolet rays, visible rays, or infrared rays) toward the
luminous coloring matter in the guidance line 1 on the floor surface. The
light-receiving device receives and measures light of another wavelength
(ultraviolet rays, visible rays, or infrared rays) emitted from the
luminous material absorbing the light emitted from the light-emitting
device. An infrared sensor is used in cases receiving infrared light. The
two photosensors 5, 5' are aligned in the direction perpendicular to the
longitudinal direction of the guidance line 1 so that they are located
within the width of the guidance line 1.
Receiving information signals from the photosensors 5, 5' the control unit
6 sends a control signal to one or both of the drive motors 11, 11'.
Namely, when the photosensors 5, 5' are located right above the guidance
line 1, they receive a predetermined level of emitted light from the
luminous material in the guidance line 1 to send normal signals to the
control unit 6. If the floor washing machine V deviates from the track,
photosensor 5 or 5' fails to receive the light from the guidance line 1 to
send an abnormal signal.
When receiving the abnormal signal, the control unit 6 immediately sends a
command signal to the drive motors 11 or 11' to control the drive wheels 3
or 3' so as to correct the traveling direction of the floor washing
machine V.
The washing device is so arranged that a drive motor 12 rotates the rotary
brush 7 to wash the floor surface 2 while supplying a detergent from the
detergent tank 8. The squeegee 10 draws in dirty water after washing by
suction to put it into the dirty water tank 9. Since the detergent tank 8
is a flexible package located inside the dirty water tank 9, it contracts
as the detergent amount decreases. That decrease increases the capacity of
the dirty water tank 9 and thus it can hold a larger amount of dirty
water.
Industrial Applicability
The operation of the water floor washing machine V of the above embodiment
is next described. First, while rotating the rotary brush 7 by the drive
motor 12, the detergent in the detergent tank 8 is supplied to the center
portion of the rotary brush 7. The rotary brush is lowered onto the floor
surface 2 to wash the floor surface.
At the same time, the left drive motor 11' and right drive motor 11 are
activated to rotate the drive wheels 3' and 3 so as to make the floor
washing machine V advance. At the starting point, the two photosensors 5
and 5' are manually located right above the guidance line 1. After the
floor washing machine V starts advancing, the squeegee 10 is lowered onto
the floor surface 2 to draw in the dirty water by suction.
As the floor washing machine V advances, it may start to deviate from the
guidance line 1. For example, if it deviates to the right from the
guidance line 1, the right photosensor 5 deviates from the guidance line
1, as shown in FIG. 2, and the sensor 5 sends an abnormal signal to the
control unit 6. The control unit 6 immediately sends a control signal to
the drive motors 11, 11' to increase the rotation speed of the right drive
wheel 3 or to decrease the rotation speed of the left drive wheel 3'. The
track of the floor washing machine V is then corrected to the left so as
to locate the right photosensor 5 again on the guidance line 1.
Conversely, if the floor washing machine V deviates to the left, the left
photosensor 5' deviates from the guidance line 1 to generate an abnormal
signal, whereby the track or direction of the machine is corrected to the
right.
The above embodiment is so arranged that the two photosensors 5 and 5' are
aligned within the width of the guidance line 1. A deviating direction is
detected by a first deviating photosensor 5 or 5'. However, the present
invention is by no means limited to this arrangement. For example, a
possible arrangement is such that two photosensors 5 and 5' are arranged
on either side of the guide line 1 and that an abnormal signal is
generated when either one of the left or right photosensors 5, 5' goes
into the guidance line 1.
In another arrangement, the number of the photosensors 5, 5' can be
increased to be set at suitable positions, whereby a more precise guidance
control can be performed.
The above embodiment was explained as to the guidance control method with a
plurality of photosensors 5, 5'. However, the control can be done with a
single photosensor 5 employing such an arrangement that the traveling
drive apparatus is preliminarily set with a tendency for the floor washing
machine V to deviate to a specific side (to the right or to the left) of
the guidance line 1. In this embodiment, the correction of track is always
made only in one direction, as shown in FIG. 3, in the same general manner
as described for FIG. 2 above, except there is only one sensor to generate
an abnormal signal.
Although the above embodiment showed the floor washing machine V, the
self-advancing vehicle of the present invention is not limited to this.
The present invention can be applied to any self-advancing vehicle which
can travel on a surface of by automatic operation. Further, the traveling
device of the self-advancing vehicle is not limited to that in the above
embodiment, but any other traveling device than that in the above
embodiment can be employed as long as it has a mechanism capable of
automatically traveling in accordance with the control signal from the
control unit to the steering means such as the motors 11, 11' and driving
wheels 3, 3'.
Table 1 shows specific examples of luminous materials dissolved in a
solvent, which may be used in the present invention.
TABLE 1
______________________________________
A B C
______________________________________
(1) EB-501 0.03 -- --
(2) EG-302 -- 0.02 --
(3) Kayact Luminous C-B
-- -- 0.05
Benzene 99.97 99.98 50.00
Ethanol -- -- 49.95
Water -- -- --
TOTAL 100.0 100.0 100.0
______________________________________
(1) A luminous coloring material manufactured by Mitsui Toatsu Kagaku,
which converts ultraviolet light into blue light (433 nm) to be emitted.
(2) A luminous color material manufactured by Mitsui Toatsu Kagaku, which
converts ultraviolet light into light of yellow green (524 nm) to be
emitted.
(3) A photochromic coloring material manufactured by Nippon Kayaku.
Table 2 shows specific examples of ultraviolet-absorbing coloring materials
mixed in floor polish.
TABLE 2
______________________________________
D E F
______________________________________
EB-501 0.02 -- --
EG-302 -- 0.03 --
Kayact Luminous C-B
-- -- 0.05
Acrylonitrile-styrene
35.00 35.00 28.00
copolymer emulsion
(35%)
Tributoxyethyl 1.80 1.80 1.00
Phosphate
Diethylene glycol
3.00 3.00 3.00
monoethyl
ether
Dipropylene glycol
2.00 2.00 2.00
monoethyl
ether
(1) Topco .RTM. LR-400-30WS
2.00 2.00 1.70
(30%)
(2) Hitec .RTM. E-4B-S
3.50 3.50 2.45
(40%)
Ammonium zinc carbonate
4.00 4.00 3.20
Solution (12%)
Zonyl .RTM. FSE (14%)
0.08 0.08 0.08
(3) Deltop .RTM.
0.10 0.10 0.10
Preservative
Water 48.50 48.49 58.42
TOTAL 100.0 100.0 100.0
______________________________________
(1) A resin fumaric ester gum ammonium solution produced by Toyo Petrolit
Co., Ltd.
(2) An oxidized polyethylene wwax emulsion produced by Toho Chemical
Industry Co., Ltd.
(3) Halogenated acetoamide monoiodide from Takeda Chemical Dindustries,
Ltd.
Many embodiments and modifications of the present invention may be
constructed without departing from the spirit and scope of the invention.
It should be understood that the present invention is by no means limited
to the specific embodiments or examples described in the specification.
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